The investigation of the fractionation of S compounds in forest soils is a powerful tool for interpreting S dynamics and S biogeochemistry in forest ecosystems. Beech stands on high pH ...(nutrient-rich) sites on Flysch and on low pH (nutrient-poor) sites on Molasse were selected for testing the influence of stemflow, which represents a high input of water and dissolved elements to the soil, on spatial patterns of sulfur (S) fractions. Soil cores were taken at six distances from a beech stem per site at 55 cm uphill and at 27, 55, 100, 150 and 300 cm downhill from the stem. The cores were divided into the mineral soil horizons 0–3, 3–10, 10–20, 20–30 and 30–50 cm. Soil samples were characterized for pH, C
org
, pedogenic Al and Fe oxides and S fractions. Sequential extraction by NH
4
Cl, NH
4
H
2
PO
4
and HCl yielded readily available sulfate-S (
RAS
), adsorbed sulfate-S (
AS
) and HCl-soluble sulfate-S (
HCS
). Organic sulfur (
OS
) was estimated as the difference between total sulfur (
ToS
) and inorganic sulfur (
RAS
+
AS
+
HCS
). Organic sulfur was further divided into ester sulfate-S (
ES
, HI-reduction) and carbon bonded sulfur (
CS
). On Flysch,
RAS
represented 3–6%,
AS
2–12%,
HCS
0–8% and
OS
81–95% of
ToS
. On Molasse,
RAS
amounted 1–6%,
AS
1–60%,
HCS
0–8% and
OS
37–95% of
ToS
. Spatial S distribution patterns with respect to the distance from the tree stem base could be clearly observed at all investigated sites. The presented data is a contribution to current reports on negative input–output S budgets of forest watersheds, suggesting that mineralization of
OS
on nutrient rich soils and desorption of historic
AS
on nutrient-poor soils are the dominant S sources, which have to be considered in future modeling of sulfur.
A composite material, based on glass fibres and a siloxane matrix, was designed for application in bone surgery. On the composite surface, open pores were produced, the sizes of which were in the ...range 0.2-0.4 mm, 0.4-0.6 mm, and > 0.6 mm, and the matrix was enriched with hydroxyapatite (HAp) powder of 5 micron grain size. Samples of the composite were tested mechanically and for wettability, and their biological properties were tested in vitro and in vivo, complemented by tests of the composite-bone tissue interfacial bonding strength. A simple method is suggested for preparing a composite based on inexpensive biologically-neutral components, which displays mechanical properties similar to those of human bone and can be used in the form of elements where no adherence to the human bone is desirable, e.g., bone plates for internal osteosynthesis of long bones. When the composite structure is modified by adding HAp and creating optimal open pores (0.4-0.6 mm) on the composite surface, stimulation of the adhesion of the bone cells to the composite increases and this can be successfully used in applications of fill-in and replacement elements. 29 refs.
Nanometer-sized liquid droplets formed at temperatures below the bulk melting point become supercooled as they grow through Ostwald ripening or coalescence and can be exploited to grow nanowires ...without any catalyst. We used this simple approach to synthesize a number of highly crystalline metal oxide nanowires in a chemical or physical vapor deposition apparatus. Examples of nanowires made in this way include VO2, V2O5, RuO2, MoO2, MoO3, and Fe3O4, some of which have not been previously reported. Direct evidence of this new mechanism of nanowire growth is found from in situ 2-dimensional GISAXS (grazing incidence small angle X-ray scattering) measurements of VO2 nanowire growth, which provides quantitative information on the shapes and sizes of growing nanowires as well as direct evidence of the presence of supercooled liquid droplets. We observe dramatic changes in nanowire growth by varying the choice of substrate, reflecting the influence of wetting forces on the supercooled nanodroplet shape and mobility as well as substrate−nanowire lattice matching on the definition of nanowire orientation. Surfaces with defects can also be used to pattern the growth of the nanowires. The simplicity of this synthesis concept suggests it may be rather general in its application.
Composite materials based on a polyamide fabric and a polysiloxane matrix were designed for application in bone surgery. In order to increase the bioactivity, 2, 5, 10, 15, 20 and 25 vol% of ...nano/micro hydroxyapatite (HA) and tricalcium phosphate (TCP) were added. The effect of the additives on the mechanical properties was studied. Changes in the inner structure of the composites were investigated by image analysis. Compared with the micro particles, the nano additives had a more favourable effect on the mechanical properties. From the point of view of the final application of the composites as substitutes for hard tissues, 10-15 vol% of nano additives is optimum: in this case both the optimisation of the toughness and the increase in the ultimate strength in bending occur without any changes in the inner structure of the composite.
Fabric composites for use as bone plates and bone substitutes were investigated. The composites were composed of E- and R-glass fibres and a matrix based on polysiloxane resin. The effect of ...short-term storage in a tissue culture medium on the composite material elution was studied and, subsequently, their mechanical properties were tested. It was concluded that the composites exhibited almost no change in their material properties after storing in the medium used and drying. 11 refs.
This paper shortly describes a conception of H.323 videoconference networking and security module that is part of integrated multimedia support system for research consortia. First, the requirements ...of this videoconference system are presented. This is followed by a description of common security conceptions. H.323 network suffers from the fact that the protocol itself codes the IP addresses of videoconference participants in the application level data. We propose here a unified system which solves this problem and allows an interconnection of private H.323 networks over the common public network. Results from our previous research are used to establish and maintain a secured communication tunnel and therefore all H.323 communications are encrypted and authenticated. In conclusion, a brief summary of the results obtained during verification of this security conception is given.
The proposed Long Baseline Neutrino Observatory (LBNO) initially consists of \(\sim 20\) kton liquid double phase TPC complemented by a magnetised iron calorimeter, to be installed at the Pyh\"asalmi ...mine, at a distance of 2300 km from CERN. The conventional neutrino beam is produced by 400 GeV protons accelerated at the SPS accelerator delivering 700 kW of power. The long baseline provides a unique opportunity to study neutrino flavour oscillations over their 1st and 2nd oscillation maxima exploring the \(L/E\) behaviour, and distinguishing effects arising from \(\delta_{CP}\) and matter. In this paper we show how this comprehensive physics case can be further enhanced and complemented if a neutrino beam produced at the Protvino IHEP accelerator complex, at a distance of 1160 km, and with modest power of 450 kW is aimed towards the same far detectors. We show that the coupling of two independent sub-MW conventional neutrino and antineutrino beams at different baselines from CERN and Protvino will allow to measure CP violation in the leptonic sector at a confidence level of at least \(3\sigma\) for 50\% of the true values of \(\delta_{CP}\) with a 20 kton detector. With a far detector of 70 kton, the combination allows a \(3\sigma\) sensitivity for 75\% of the true values of \(\delta_{CP}\) after 10 years of running. Running two independent neutrino beams, each at a power below 1 MW, is more within today's state of the art than the long-term operation of a new single high-energy multi-MW facility, which has several technical challenges and will likely require a learning curve.
One of the main goals of the Long Baseline Neutrino Observatory (LBNO) is to study the \(L/E\) behaviour (spectral information) of the electron neutrino and antineutrino appearance probabilities, in ...order to determine the unknown CP-violation phase \(\delta_{CP}\) and discover CP-violation in the leptonic sector. The result is based on the measurement of the appearance probabilities in a broad range of energies, covering t he 1st and 2nd oscillation maxima, at a very long baseline of 2300 km. The sensitivity of the experiment can be maximised by optimising the energy spectra of the neutrino and anti-neutrino fluxes. Such an optimisation requires exploring an extended range of parameters describing in details the geometries and properties of the primary protons, hadron target and focusing elements in the neutrino beam line. In this paper we present a numerical solution that leads to an optimised energy spectra and study its impact on the sensitivity of LBNO to discover leptonic CP violation. In the optimised flux both 1st and 2nd oscillation maxima play an important role in the CP sensitivity. The studies also show that this configuration is less sensitive to systematic errors (e.g. on the total event rates) than an experiment which mainly relies on the neutrino-antineutrino asymmetry at the 1st maximum to determine the existence of CP-violation.
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